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| author | Will Deacon <will.deacon@arm.com> | 2018-07-31 13:09:03 +0200 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2018-07-31 13:10:38 +0200 |
| commit | dcab90d90935f990407c86b671a7f1ac285d106c (patch) | |
| tree | 6e5176cd76acbbd9882b50b921d66fb9122771f7 | |
| parent | arm64: sdei: Mark sdei stack helper functions as static (diff) | |
| download | linux-dcab90d90935f990407c86b671a7f1ac285d106c.tar.xz linux-dcab90d90935f990407c86b671a7f1ac285d106c.zip | |
arm64: kexec: Add comment to explain use of __flush_icache_range()
Now that we understand the deadlock arising from flush_icache_range()
on the kexec crash kernel path, add a comment to justify the use of
__flush_icache_range() here.
Reported-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
| -rw-r--r-- | arch/arm64/kernel/machine_kexec.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c index 4c0eb30bfede..f6a5c6bc1434 100644 --- a/arch/arm64/kernel/machine_kexec.c +++ b/arch/arm64/kernel/machine_kexec.c @@ -184,8 +184,15 @@ void machine_kexec(struct kimage *kimage) /* Flush the reboot_code_buffer in preparation for its execution. */ __flush_dcache_area(reboot_code_buffer, arm64_relocate_new_kernel_size); + + /* + * Although we've killed off the secondary CPUs, we don't update + * the online mask if we're handling a crash kernel and consequently + * need to avoid flush_icache_range(), which will attempt to IPI + * the offline CPUs. Therefore, we must use the __* variant here. + */ __flush_icache_range((uintptr_t)reboot_code_buffer, - arm64_relocate_new_kernel_size); + arm64_relocate_new_kernel_size); /* Flush the kimage list and its buffers. */ kexec_list_flush(kimage); |